Process for treating metals



Sept. 15, 1931. H. H. s=reUT Y 1,822339 PRCCESS FOR TREATING METALS Original Filed May 28, 1926 4 Sheets-Sheet l Sept. l5, 1931. H. H. sTouT 1,822,939

PROCESS FOR TREATING METALS Original Filed May 28, 1926 4 Sheets-Sheet 2 Sept. l5, 1931. H. H. sTouT Pnocss FoR TREATING METALS Original Filed May 28, 1926 4 Sheets-Sheet 3 IEVNTER Y Tl/ A ORNEY Sept. 15, 1931. H, H, sTouT 1,822,939

PROCESS FORA TREATING METALS Original Filed May 28, 1926 4 Sheets-Sheet 4 Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE HARRY H. STOUT, 0F CLIFTON, ARIZONA, ASSIGNOR, BY MESNE ASS-IGNIIIENTS,v TO COALESCENCE PRODUCTS COMPANY, INC., A CORPORATION OF NEW YORK PROCESS FOR TBEATING Continuation in part of lapplication Sgrial No. 111,887,

1928. Serial This invention relates to a method of treating metals for the purpose of prciducing a purified, homogeneous mass. A

A particular object is the treatment of metallic particles with suitable fluids at tem peratures below vthe melting point of the metal being treated to remove impurities that may be present between the crystals of the metal.

A further feature of the invention resides in subjecting the metal, purified as above or in any suitable manner, to mechanically applied pressure at suitable temperatures below the melting point of the metal in order to coalesce the particles into a homogeneous mass, and cause-new crystal grain growth throughout the mass.

The invention further contemplates the utilization of mechanically applied pressure to simultaneously coalesce and extrude the metal in the form of a rod or bar.

In the drawings:

Fig. 1 is a cross-section through a bailing press, showing the parts in preliminary position.

Fig. 2 is a view similar to Fig. 1 but with the parts in a different position.

Fig. 3 is a horizontal section through apparatusfor cleaning and coalescing the particles.

Fig. 4 is a view similar to Fig. 3 but with the parts in another operative position.

Fig. 5 is a view similar to Fig.` 3 but with the parts in still another operative position.

This application is in part a continuation of copending application Ser. No.- 111,887, filed May 26, 1926.

. The invention is adapted for use with various` metals, particularly copper'and zinc, and will be disclosed in detail as applied to copper.

The process can be applied to any form of solid co )er` such as broken ca-thodes, sera copper, s ottecl copper, etc. These forms of copper ordinarily1 contain impurities located between the crystals of pure copper. In particular, cathode copper contains copper sulphate and other impurities from the electrolyte.

` It has been found that unser saitaie conlel May 28, 1926. This application led August 15, No. 299,665.`

ditions it is possible to cause a cleaning fluidf to permeate between the crystals to remove the impurities and cleanthe surfaces of the crystals.

If the metal is thereafter suitably handled `to prevent the return of impurities, and is subjected to suitable elevated temperatures below themelting point of the copper and to mechanically applied pressure, the mass of particles can be Acoalesced into a homogeneous mass'. The resulting piece of metal body 13 of the press. The head block 14 is then moved to the closed position of Fig- 2, and the plunger 15 is actuated to apply pressure to the char e. grec of compression has been obtained the plunger is backed away, head block 14 is withdrawn, extension sleeve 16 is raised, and plunger 15 again advanced to eject the formed billet 17 to the dotted line position of Fig. 2.

The billets are then transferred to the mechanism illustrated in Fig. 4 for treatment. Reference character 18 indicates a gas-tight electrical furnace in which the billets are treated to the action of a cleaning fluid at an elevated temperature below the melting point of copper. A gas lock 19 permits the feeding of billets into the furnace without the escape of fluid from the furnace. The cleaning fluid, which is preferably hydrogen or blue water gas, enters by inlet 20 and is Withdrawn through outlet 21. Other suitable cleaning fluids may be used,'su ch as nitrogen, steam, carbon dioxide. and hydrocarbon gases, and in each case the cleaning fluid must be free from any substance that `would injuriously affect the finished copper.

After the desired vvde- The billets are moved through the furnace by any preferred conveyor system (not shown) and are meanwhile heated to about 1500 F. Duringthe passage through the furnace the cleaning fluid permeates the mass of the billet, removing impurities and cleaning the crystal surfaces.

The billet must now be maintained in a neutral or non-injurious atmosphere while it is being pressed into a solid mass. In the apparatus illustrated the billet is passed through a receiving cham-ber filled with 'the cleaning fluid to a preliminary position in front of the coalescing chamber 22. The feed plunger 23 now pushes the billet into the coalescin chamber, and the sliding head block 24 Fig. 4) for the coalcscing chamber is closed and supported in any suitable manner, as by the plunger 23. The coalescing lunger 25 is now moved toward the right y means of yoke 26 and hydraulic cylinders 27, pressing the apertured die block 28 against the billet. This movement of the plunger 25 compresses the billet and coalesces the particles thereof. At the same time the solidified copper is extruded through the apertured die block in a rod or wire of a'shape corresponding to the aperture in the die block.

The stroke of the coalescing plunger is stopped before the entire billet has been extruded, and when it is approximately in the position of Fig. 4. The head block 24 is removed and feed plunger 23 is used to push back the unextruded stub to the left of the coalescing chamber, as shown in Fig. 5. A fresh billet is then fed into'the coalescing` chamber, and the process is repeated. In this way each new billet is coalesced with the stub of the last billet to form a continuous solid mass.

Summarizing the process, it may be said to consist of the following steps:

1. (Optional.) Pressing broken copper while cold into billets.

2. Treating with cleaning fluid at an elevated temperature below the melting point of the copper to remove impurities.

3. Maintaining the copper out of contact with injurious substances and subjecting it to mechanically applied pressure .sufficient to bring into physical contact all faces of the copper particles, to drive out the gas from between the particles and to induce new crystal grain growth across the old particle faces. 4. (Optional.) Extruding the copper through a die.

By using this process it is possible to produce a copper of the purity of 99.995 per cent. While a preferred apparatus for. carrying out the process has been disclosed herein, it should be understood that various changes may be made in the layout and in the mechanical details.

I claim: 1. The process of refining a metal which consists of treating the crystalline metal to Y remove impurities from crystal surfaces, the treatment being carried out at a -raised temperature below the melting point of the metal, maintaining the metal thereafter and.A

until the end of the process in a suitable gaseousatmosphere which will pass out of the metal` without leaving blow holes or adverse; ly affecting the physical properties of the metal, and then subjecting the metal to Vmcchanically applied pressure sufficient to press the cleaned surfaces into close adhesive contact. s

2. The process of refining a metal which consists of treating the crystalline metal to 'remove impurities from crystal surfaces, the treatment `being carried out at a raised temperature below the melting point .of the metal, maintaining the metal thereafter and until the end of the process in a suitable gaseous atmosphere which will pass out ofthe metal without leaving blow holes or adversely affecting the ,physical properties of the metal and then subject-ing the metal to mechanically applied pressure sufficient to press the cleaned surfaces into close adhesive' contact, the pressing being effected at a suitable raised temperature below the lmelting point of the the surface of a plurality of separate metal-4 lic pieces to remove surface impurities, thereafter maintaining the vpieces in a non-injurious atmosphere which prevents return of the surface impurities, and Isubjecting the particles, while maintained in said non-injurious atmosphere, to mechanically applied pressure to coalesce thevpa-rticles and to extrude them as a solid mass.

5. The process of producinga solid mass practically pure copper which vcomprises removing impurities from copper particles, thereafter maintaining the particles in a noninjurious atmosphere which prevents return of the impurities, and subjecting the particles. -while maintained in said noninjurious atmosphere, to pressure sufficient to integrate the same, while subjecting the particles to a temperature suiiicient to cause crystal grain growth across the old surface boundaries.

6. The process of producing a solid mass of practically pure copper which comprises removing impurities from copper particles by means of a reducing gas, thereafter maintaining the particles fin a non-injurious atmosphere which prevents return of the impurities, and subjecting the particles, while maintained in said non-injurious atmosphere, to pressure suflicient to integrate the same, while subjecting the particles to a temperature sufiicient to cause crystal grain growth across the old surface boundaries.

7. The process which comprises removing impurities from copper particles, thereafter maintaining the particles in a non-injurious atmosphere which prevents return of the impurities, heatingthe particles to a temperature suflicient to: cause crystal grain growth and applying pressure sufficient to coalesce the particles into a solidmass and to simultaneously extrude the mass.

8. The process which comprisesremoving impurities from copper particles by means of a reducing gas, thereafter maintaining the particles in a non-injurious atmosphere which prevents return of the impurities, heating the particles to a temperature sufiicient to cause crystal grain growth and applying pressure sufficient to coalesce the particles into a solid mass and to simultaneously extrude the mass.

9. The process which comprises removing impurities from copper particles, thereafter maintaining the particles in a non-injurious atmosphere which prevents return of the impurities, subjecting a charge of the particles to simultaneous heat and pressure suflicient to cause crystal grain growth and coalesce the particles into av solid mass and to simultaneously extrude the mass, and similarly coalescing and extruding a second charge against the-end of the first charge to produce a continuous homogeneous piece.

l0. The process which comprises'removing impurities from copper particles, thereafter maintaining the particles in a non-injurious atmosphere which prevents return of the impurities, a charge of the particles being maintained in an extrusion chamber at an elevated temperature below the melting point of the copper While sufficient pressure is applied to cause crystal grain growth and coalesce the particles into a solid mass and to simultaneously extrude the mass, stopping the extrusion at a suitable point to leave a stub of the first charge in the extrusion chamber, inserting a second charge ofthe particles into the extrusion chamber, bringing about suitable conditions of heat and pressure to cause the second charge to coalesce with itself and with the first charge while continuing the extrusion to cause both charges to issue as a continuous, homogeneous mass of copper.

1l. The method of producingr a solid metallic mass from an aggregate of smaller metallic particles which comprises, first cleansing the surface of the particles by treatment with suitable fluid 1at a suitable raised temperature below the melt point of the particles, and thereafter, and until the process is complete, maintaining the cleansed particles in a medium Which'will not permit the return to the surface of the particles of sufficient impurities to prevent coalescence in the next step of the process, and submitting the aggregate of cleaned particles to pressure, at al raised temperature below the melt point of thJe particles, sufiicient to coalesce the particles into a solid mass by causing crystal grain growth to take places across all ad]acent particle boundaries. A

12'. The method of producing a solid metallic mass from an aggregate of smaller metallie particles which comprises, first cleansing the surface of the particles by treatment with suitable fluid at a suitable raised temperature below the melt point of the particles, and thereafter, and until the process is complete, maintaining the cleansed particles in a medium which will not permit the return to' the surface of the particles of sufficient impurities to preventcoalescence inthe next step of the process, and submitting the aggregate of cleaned particles to pressure, at a raised temperature below the melt point'of the particles, sufficient to coalesce -the particles int(I a solid mass by causing crystal grain growth to take place across all adjacent particle boundaries and to extrude the mass, and similarly coalescing and extruding a second charge against the end of the first charge, thereby causing crystal grain growth across the original boundary between the first and second charges and producing a single, homogeneous piece.

13. The method of producing a solid mass of copper which comprises heating an aggregate of copper particles to an elevated tem,- perature below 'the' meltingr point of'copper, treating the aggregate with fluid suitable to permeate the aggregate and to remove impui-ities from the surfaces of individual particles, and thereafter and' until thc end of the process maintaining the'aggregate in a medium that will not permit the return to the surfaces of the particles of impurities sufficient in amount to prevent complete subsequent `grain growth between all adjacent particle surfaces, and subjecting the aggregate at an elevated temperature below the melting point of copper to pressure sufliof copper which comprises compressing broken brittle cathode 'copper into a billet, heating the billet to an elevated temperature below the melting point .of copper, treating the billet with a Huid that is reducing to oxides of .copper and that is suitable for removing impurities from the surfaces of individual particles within the billet, and thereafter until the process is complete, maintaining the billet ifi a medium that is non-injurious to the copper, and subjecting the billet, at a temperature of approximately 1500o F. to pressure sufficientito press allof the particles of the billet into close contact, thereby causing crystal grain growth to take place across all the adjacent particle boundaries and producing a hmogeneous mass of copper.

15. The method of producing a solid mass of copper which comprises' compressingY 'broken brittle ""cathode copper into a billet,

place across all the adjacent particle boundaries and producing a homogeneous mass of copper, extruding the mass, coalescing a second charge against the endof the first charge and extruding the second charge to form the two charges into a single, homogeneous 1ece.

16. Theprocess of extruding a meta1 body which comprises providing an extrusion chamber having an extrusion opening smaller than the bore of the chamber, maintaining ivithin the chamber an atmosphere non-injurious to the metal and which will prevent the return of surface impurities to a charge of metal within the chamber, passing a charge of cleansed metal into the. chamber, subjecting the charge to hea-t and pressure sufiicient Ato eXtrude part of the charge, releasing the pressure while a stub of the charge remains in the bore of the chamber, passing a second charge into the chamber, subjecting the second charge to heat and pressure sufficient to coalesce the second charge with the stub of the first charge and to extrude the second charge, thereby causing crystal grain growth across ythe original boundary between the rst and second having anextrusion opening smaller than the bore of the chamber, maintaining within the chamber an atmosphere non-injurious to copper and which will prevent the return of surface impurities to copper within the'chamber, passing a charge of cleansed copper into the chamber, subjecting the charge to heat and pressure suflicient to extrude part o the charge, releasing the pressure while a'stub of the charge remains in the bore of the chamber, passinor a second charge into the chamber, subjectlng the second charge toheat and pressure sufiicient to coalesce the second charge with the stub of the first charge and to extrude the second charge, thereby causing crystal grain growth across the original boundary between the first and second lcharges and extruding both charges, and

and extruding successive similarly joinin charges to pro uce a continuous mass of copper.

In testimony whereof I affix my signature.

HARRY H. STOUT.

charges and extruding both charges, and

similarly joining and extruding successive charges to produce a continuous metal body.

17. The process of extruding copper which comprises providing an. extrusion chamber 

